The present inventors'commonly assigned co-pending patent application Ser. No. 08/092,320 filed 14 Jul. 1993 discloses a fuel pressure regulator that is disposed inside a fuel tank. Although that pressure regulator spills excess fuel back to the fuel supply inside the tank, that sort of a system avoids the use of a separate return conduit from the engine back to the tank since the pressure regulator is inside the tank rather than on the fuel rail assembly. Eliminating the return conduit can often provide meaningful cost and space savings, but when doing so places the fuel pressure regulator more remote from the fuel rail assembly, it may be necessary to invoke measures for assuring that the remoteness does not impose undesired consequences on the performance of the fuel rail assembly. Moreover, a tank-mounted pressure regulator is typically not conveniently disposed for direct intake manifold vacuum compensation, and even if engine manifold vacuum were to be conveyed to it, a vacuum conduit from the engine to the fuel tank would be needed, thereby at least to some extent defeating the purpose of eliminating the fuel return conduit.
The present invention relates to a new and unique fuel pressure regulator that both enables the fuel pressure regulator to be mounted on the fuel rail assembly, where it can be close to the fuel injectors, and avoids the use of a separate fuel return conduit from the fuel rail assembly to the tank. Moreover, the inventive fuel pressure regulator retains intake manifold vacuum compensation by means of a control chamber to which intake manifold vacuum Can be conveniently conveyed through a short conduit from a nearby vacuum port on the engine's induction system.
Further features and advantages will be seen from the following detailed description of a presently preferred embodiment. Claims and drawings accompany the description, and the drawings and description disclose the best mode contemplated at this time for carrying out the invention.